Climate

Ozone Hole over Antarctica Ban on fluorocarbons began 1979

Solar Radiation Albedo (Surface Reflectivity) Albedo refers to ratio of the amount of reflected light to incident light. The higher the number the greater the proportion of light is reflected back. Glaciers and ice packs have an albedo of (80-90%), while oceans and forests have an albedo of around 0.05 (5%). On average, 30% of solar radiation is immediately reflected back into space.

Global Map of Land Albedo

Solar Radiation Temperature Change with Latitude Conclusion: the greater the angle light strikes the earth, the greater amount of area over which each unit of energy is spread.

Solar Radiation Occurs in a range of wavelengths represented by the electromagnetic spectrum. Reaches Earth's atmosphere in the form of ultraviolet radiation, visible light, and infrared radiation. Incoming short and intermediate wavelength radiation may be: absorbed by gases in the atmosphere, reflected back into space from the atmosphere or earth's surface, or absorbed by the earth's surface.

Solar Radiation Incoming and outgoing long wavelength radiation is absorbed by water vapor, carbon dioxide, and other gases in the atmosphere. The greenhouse effect occurs when long wavelength radiation is absorbed in the troposphere

Solar Patterns are the Basis of Climate Earth The distance through atmosphere is different at high versus low latitudes.

The Earth at 23.5 O Tilt Seasonal Variation The Earth at 23.5 O Tilt Seasonal Variation.

Atmosphere Distinct zones of contrasting temperatures and compositions. Thermosphere - high temperature (includes ionosphere - auroras). Thermosphere - high temperature (includes ionosphere - auroras).. Mesosphere - low temperatures. Stratosphere - high levels of Ozone. Absorbs ultraviolet rays. Troposphere - nitrogen and oxygen; weather..

Structure of Atmosphere The atmosphere can be divided into four thermal layers: troposphere, stratosphere, mesosphere, and thermosphere. The boundary with space is at an altitude of approximately 500 km. Air temperatures decrease upward in the troposphere (to a minimum of approximately -50 o C) which contains our weather systems. Bulk of atmospheric gases (~75%) in this layer.

Structure of Atmosphere Temperatures increase with altitude in the stratosphere as ozone absorbs incoming solar radiation. Temperatures decline again in the mesosphere but increase in the thermosphere.

Air Mass Formation

General Air Patterns

Atmospheric Circulation Pattern The sun, through heating of land and air, drives the earth’s patterns of rains, winds, and ocean currents.

Global Patterns of Air Circulation/Precipitation Air rises at the equator (equator = hot) First convection cell is highest because most energyAir rises at the equator (equator = hot) First convection cell is highest because most energy Adiabatic coolingAdiabatic cooling Rain occurs (cool air holds less water).Rain occurs (cool air holds less water). Air from the North and South comes in to replace it.Air from the North and South comes in to replace it. Coriolus effect - air is deflected because of momentumCoriolus effect - air is deflected because of momentum.

Air Pressures

Areas of High and Low Pressure Generate Surface Winds

Coriolus Effect

Coriolus Effect Responsible for where wind blows from; wind patterns influence regional weather.

Winds Wind is the horizontal movement of air from areas of high to low pressure. High pressure regions are dominated by cold, descending air, while low pressure areas are associated with warm, rising air masses. Winds blow perpendicular to the pressure gradient. Winds are deflected from their course by the Coriolis Effect

Ocean Currents Due to Coriolis Effect and Land Masses

Ocean waters warmed in the equatorial regions transport heat energy to other parts of the globe.

Circulation of Warm and Cool Ocean Waters has a Moderating Effect on Coastal Cities

Effects of Upwelling and Downwelling on Currents When the wind blows parallel to a Northern Hemisphere coastline and the ocean is to the right of the wind direction, upwelling can result. Wind in the opposite direction produces downwelling.

Upwellings Bring Nutrients to Surface

ENSO (El Niño – Southern Oscillation) The Southern oscillation is a phenomenon that refers to the see-saw effect of surface air pressures in the Eastern and Western Pacific Ocean. For Example, when air pressure recordings are high in Tahiti, they are low in Eastern Australia. Also noted was a cycle of varying Pacific Ocean temperatures which occurs annually on a small scale. This was recognized by Peruvian fishermen who called it El Niño (Christ Child) because it occurred during the winter close to Christmas.

Normally, have warm waters and heavy precipitation in the western Pacific. El Niño, have warm waters migrate to the eastern Pacific along with the convective cell and increased rainfall.

El Niño and La Niña ñ La Niña (cold conditions) Normal Conditions ñ El Niño (warm conditions)

Climate Changes Associated with ENSO

Weather Phenomenon are Produced by the Circulation of Air and Water. ThunderstormsHurricanesTornadoesDroughtsFloods

Mountain Effects on Precipitation

Six Climate Regions

Two climate conditions, temperature and precipitation, determine the terrestrial regions. Biomes